engine, heads, compression.. HUH??

[Archer]

hey does anyone in here have a site or a book they can push me towards that explains about compression ratios, ci, what will and what wont work?

I have been doing a TON of research and people are talking alot about 4.00x4.05 or whatever,

Im looking at doing what tom did, but the LS1 is a little costly. so I was looking to build a 5.3L or 6.0L which I think is the LQ4 maybe? But they are talking about building a stroker engine. but there are tons of things they are talking about "engine wise" that I dont understand, so instead of asking a billion questions, I figured I would read up on it before I started asking the real question "would this 6.0L aluminum head fit on this block"?


anyone have a website that would explain things like this? Cams, ratios, compression... I want a V8, got a killer LOCAL deal on my 2000. Found a company to reprogram the PCM, but all these damn numbers are comfusing. Oh and these LQ4, LQ9, L79 also are a bit confusing for me.
Thanks guys
Archer

[ssms5411]

Re: engine, heads, compression.. HUH??

I would post on LS1.com or Z28.com I'm sure they could help you.

[cam98aro]

Re: engine, heads, compression.. HUH??

there is a lot of very knowledgeable people at team camaro

although all of the questions you have asked can be done with a google search, its not a very hard thing to understand.

[Archer]

Re: engine, heads, compression.. HUH??

well I figured I would ask some of the gear heads around here since I have been talking to ya'll for a while. didnt want to be a noob over there (tho ive been on there for a while reading) and have someone tell me to do a search that I've already been doing for a while..

ya know I love google, never thought about using it.

Archer

[cam98aro]

Re: engine, heads, compression.. HUH??

well I figured I would ask some of the gear heads around here since I have been talking to ya'll for a while. didnt want to be a noob over there (tho ive been on there for a while reading) and have someone tell me to do a search that I've already been doing for a while..

ya know I love google, never thought about using it.

Archer

yeah, dont get me wrong, i wasnt trying to be an *** and tell you to just search google, but you can find many many forums where people ask questions and you can get a ton of useful information.

i would suggest picking up a book like "how to rebuild your SBC" or "all about the sbc" or something.. yes i know it doesnt pertain to the v6's but any information you will find there will be spot on with the v6 engine wise (compression, decking the block, how to choose the right cam, etc)

there is very little difference between the engines and how they work.. actually any pushrod engine info you can find will help you.

what kind of information are you looking at? im sure i can help you out about things engine wise, but im not too familiar with the lsx family (so i cant help you if you want to know if you want to know "would this 6.0L aluminum head fit on this block" but if you need to know something about a cam, compression, etc. i can probably help.

[Archer]

Re: engine, heads, compression.. HUH??

whats SBC? I am trying to find the right engine (V8) that I want to drop in my car later this year. I have been hearing dropping a 5.3L is MUCH cheaper than the LS1 with similar results (not dead on). or I was looking at getting a 6.0L but both engines all I can see that people are doing (camaroZ28 and LS1tech) are people stroking the motor. Thats not what I was looking for. I found some info on it, but I guess I am just trying to understand what people are talking about because SOMEDAY I'd like to toss a little power into the V8. So far it looks like MONEY WISE, the drop out LS1 w/ trans, harness and PCM is the best buy and a good base to start a good engine mod. but decking heads, compression ratios, I know a little about compression and boring and cams.. but its more on the Sportbike side of things and they are a tad bit different. Im just looking to learn so I know what people are talking about and someday I can do the things I want to do right without paying someone to do it for me.

know what I mean? lol..

the more reading I do on the V8 sites, the more I get confused because they are doing something for PURE STRIP Power. But all in all, I'll probably start with the LS1 and go from there... there are a few books out there and a few sites that focus on the engine, but not much on the Engine in the F-body..

[cam98aro]

Re: engine, heads, compression.. HUH??

whats SBC? I am trying to find the right engine (V8) that I want to drop in my car later this year. I have been hearing dropping a 5.3L is MUCH cheaper than the LS1 with similar results (not dead on). or I was looking at getting a 6.0L but both engines all I can see that people are doing (camaroZ28 and LS1tech) are people stroking the motor. Thats not what I was looking for. I found some info on it, but I guess I am just trying to understand what people are talking about because SOMEDAY I'd like to toss a little power into the V8. So far it looks like MONEY WISE, the drop out LS1 w/ trans, harness and PCM is the best buy and a good base to start a good engine mod. but decking heads, compression ratios, I know a little about compression and boring and cams.. but its more on the Sportbike side of things and they are a tad bit different. Im just looking to learn so I know what people are talking about and someday I can do the things I want to do right without paying someone to do it for me.

know what I mean? lol..

the more reading I do on the V8 sites, the more I get confused because they are doing something for PURE STRIP Power. But all in all, I'll probably start with the LS1 and go from there... there are a few books out there and a few sites that focus on the engine, but not much on the Engine in the F-body..

sbc is small block chevy.. usually referred to the gen1 small block v8's, but the lt1's can fit into the same category also since the engines are so very similar.

basically with decking, it is cutting the block down, it gives you more compression (more power) and an even surface

compression? well its really simple its how much you compress the air on the compression stroke

more compression gives you more power, but at the same time requires you to use higher octane fuel in most cases

you can change your compression ratio many ways.. by putting domed pistons in, decking the block, smaller combustion chamber size, thinner head gasket, bore size etc.

for instance, i have a sbc with a decked block, 11:1 comp domed pistons and a 64cc chamber size, and it has around 12.5:1 compression (due to the decked block) i usually run 115 octane fuel in it

higher compression engines require higher octane fuel because the higher the octane, the less chance of detonation it will have.. the pressure of a high compression engine running 87 octane will actually combust the fuel (which is how diesel engines work) lower octane burns faster which means it will burn, and try to throw your crank back down because the fuel combusted before top dead center, which is why you hear a knocking noise.. not very good and an easy way to break a rod. meanwhile higher octane fuel will not combust under the high pressure and will give you a slower burn which makes more power because the fuel is burning for a longer period of time (yes, its confusing, most people think it is the other way around)

that is the same principle as "octane boosters" they dont actually give you more octane, it is a flame retardant made to prolong the combustion time

now speaking of cams, im sure you know this, but the higher lift means the valve opens higher, longer duration means the valves are open for a longer period of time. the lobe separation is just that, the separation of the cam lobes is smaller meaning your valves will open sooner

higher duration cams will cause your power band to move up in the rpm's so that means you will have to have smaller gears in the back (or a higher gear ratio number, however you look at it) in order to make up for the lower torque off of idle (which is also why you need a higher rpm stall in an auto)

the thing with cams is that you also need to match the compression to the cam, you cant just throw a huge cam in an engine with low compression (which a LOT of people do, and dont understand why their engine is running so crappy) higher duration cams require higher compression because the valves are open longer, the air can actually bleed out.. basically if you have a bigger cam it is possible for you to use a lower octane fuel than required for your compression ratio

bore size is pretty easy, its when you machine your engine to fit a bigger piston in it, which increases cubic inches, and in return gives you more power

this might help you understand things.. engine size is calculated by a simple formula:

bore x bore x stroke x .7854 x # of cylinders

so for a 3.8l engine it would look like this:

3.80 x 3.80 x 3.40 x .7854 x 6= 231.36 cubic inch

ls1:

3.90 x 3.90 x 3.62 x .7854 x 8= 345.85 ci

[bigbrian442]

Re: engine, heads, compression.. HUH??

Even if you get a 5.3 or 6.0 you still need all the brackets accessory's and wiring harness off a ls1 out of a F body. The F body drives are different from the Vettes and trucks. Most people stroke the LS motors because the early ones 97-99 could not be over bored and it was the only way to get more CID. Just about all LS heads will bolt to any LS block, you just need to watch the valve size on the smaller bore motors (5.7 L and smaller). As far as compression goes 11:1 is about as high as you can go on pump gas. Most 5.7 L and larger CID heads will be safe as far as compression goes. The LS6/LS2 head ( 243 casting) will put you at 10.9:1 on a stock LS1.

[Archer]

Re: engine, heads, compression.. HUH??

Thanks guys, that helps alot. Yeah I understand with the cams. Kinda the same on the sportbikes.. so all the 4.00 that makes alot more sense.. Im going to save this thread..

Archer

[flamingchicken]

Re: engine, heads, compression.. HUH??

"how to rebuild your SBC" or "all about the sbc"

a book that really helped me a ton was "Modifying small block chevy's" by John lingenfelter. breaks down alot of information on everything from different types of components to in depth on cam specs like lift advance duration and lobe center. I even let my girlfriend borrow it and she really benefited from reading it.

http://www.amazon.com/John-Lingenfel.../dp/155788238X